nRF51822 fds storage: Issue with fds_record_write

RE: nRF51822 fds storage: Issue with fds_record_write

bojan — Tue, 03 May 2022 12:21:43 GMT

Thanks for the suggestions, Kenneth!

Changing FS_OP_MAX_RETRIES or connection interval parameters did not resolve the issue.

What resolved the issue is putting the event into the scheduler queue with app_sched_event_put() API.

Writing into the FDS from withing scheduler handler function did the job for us!

Thanks in advance for your hints! I think we can close the ticket now.

Cheers,

Bojan.

RE: nRF51822 fds storage: Issue with fds_record_write

Kenneth — Tue, 03 May 2022 11:28:14 GMT

Hello,

Flash operations have very low priority compared to other softdevice taks:
https://infocenter.nordicsemi.com/topic/com.nordic.infocenter.s130.sds/dita/softdevices/s130/multilink_scheduling/priorities_and_events_intro.html

So, it may take considerably time before the flash operation completes or it can even timeout if the softdevice is not able to execute the flash operation due to other higher priority activities. What you can try is to for instance configure FS_OP_MAX_RETRIES to 1000, that should at least give more retries before it "give up".

To give the softdevice time to execute flash operations, it may help to increase the connection interval, and at least use slave latency on the link, since this will allow connection intervals to be skipped (e.g. to handle flash operations if needed).

Best regards,
Kenneth

RE: nRF51822 fds storage: Issue with fds_record_write

bojan — Tue, 03 May 2022 08:43:29 GMT

Hey, guys... here are some additional pieces of information:

when I initialize the FDS module AFTER initializing the Bluetooth module (gap, advertising, gatt, services, connection parameters), then I am able to properly write an initial value to the flash by using fds_record_write() function. FDS_EVT_WRITE event is properly detected.
However, when I establish BLE connection with the Central device and want to update the flash with fds_record_write() or fds_record_update() functions then write/update record operation was queued successfully but we never get the FDS_EVT_WRITE/UPDATE event inside the event handler.

It seems to me that the FDS module has some limitations when used in the presence of the Softdevice. I know that the Peer Manager is also using FDS. Is there anything we should do to make the FDS module works together with the Softdevice?

Some threads that are reporting similar issue (e.g. link1, link2) suggest including ${SDK_ROOT}/components/softdevice/common/nrf_sdh_soc.c file in the build. However, nRF5 SDK v12.3.0 does not contain that file. Is there anything similar we should include?

Regards,

Bojan.